Photothermographic film generally includes a base material, such as a thin polymer or paper, typically coated on one side with an emulsion of heat sensitive materials. Once the film has been subjected to photostimulation, for example, by light from a laser of a laser imaging system, the resulting latent image is developed through application of heat to the film to form a visible image.
Several types of processing machines have been developed for developing photothermographic film. One type employs a rotating heated drum having multiple pressure rollers positioned around the drum's circumference to hold the film in contact with the drum during development. Another type slides the photothermographic film over flat, heated surfaces or plates. Still another type of processor, commonly referred to as a flat-bed processor, includes multiple rollers spaced to form a generally horizontal transport path that moves the photothermographic film through an oven.
Each of these processors heats the photothermographic film to at least a desired processing temperature for a set time, commonly referred to as the dwell time, for optimal film development. As the photothermographic film is heated, some types of emulsions produce gasses containing contaminants, such as fatty acids, which may subsequently condense when coming in contact with cooler air or surfaces within the processor. This is particularly true at the location where the photothermographic film enters a processor where external ambient air may be drawn into the processor. When contacting cooler air or surfaces, the gasses may condense and contaminants, fatty acids in particular, may become deposited on the photothermographic film and subsequently be transported to other processor components. These deposits can accumulate over time and can damage processor components, cause film jams within the processor, and cause visual defects in the developed image. As such, regular maintenance may be required to address problems resulting from such contaminants, which can be costly and result in processor downtime.
It is evident that there is a need for improving thermal processors to reduce problems associated with contaminants produced during development of photothermographic film.